Freecom TAPEWARE AIT-450I Manual page 126

6.Command Specification
Data Mode - in this mode, the DATA IN phase contains buffer data only.
Descriptor Mode - In this mode a maximum of four bytes of READ BUFFER descriptor information are
returned. The drive returns the descriptor information for the buffer specified by the Buffer ID. In this mode,
the drive does not reject the valid Buffer IDs with a CHECK CONDITION status but returns 3F 68 00h when
Buffer ID is set to 0, 80 00 00h when Buffer ID is set to 1 in the READ BUFFER descriptor.
Bit 7
Byte
0
1 (MSB)
2
3
Buffer ID: The supported values are:
If an unsupported Buffer ID code is requested, the drive returns a CHECK CONDITION status with an ILLEGAL
REQUEST sense key set.
Buffer Offset: The Buffer Offset field contains the byte offset within the specified buffer from which data shall be
transferred from. The initiator should conform to the offset boundary requirements returned in the READ BUFFER
descriptor. If the target is unable to accept the specified buffer offset, it shall return CHECK CONDITION status,
shall set the Sense Key to ILLEGAL REQUEST, and set the Additional Sense Code to ILLEGAL FIELD IN CDB.
Allocation Length: The Allocation Length specifies the maximum number of bytes that the initiator has allocated for
returned data. An Allocation Length of ZERO indicates that no data will be transferred. Any other value indicates the
maximum number of bytes that will be transferred. The drive terminates the DATA IN phase when Allocation Length
bytes of data have been transferred or when all available data has been transferred to the initiator, whichever is less.
The Allocation Length must be greater than four (except in data only mode), else the drive will return a CHECK
CONDITION status with an ILLEGAL REQUEST sense key set.
6-72
Table 6-60: READ BUFFER Descriptor
6 5
Buffer ID
0 Read Interface Buffer
1 Read Group Buffer
4 3
Reserved
Buffer Capacity
Description
SONY AIT-1 Turbo drive SDX-450V series Ver.1.0
READ BUFFER
2 1 0
(LSB)